The present invention relates to a sizing means, apparatus and method for sizing a flexible tubular food casing during the stuffing thereof. In particular, the present invention relates to an adjustable and reuseable sizing means together with a method and apparatus for using the sizing means.
Automatic and semiautomatic systems for stuffing food casings with a variety of food products are well known in the meat packing industry. For production of encased products on a fully automated basis, shirred casing is used. Shirred casing is a relatively long continuous length of casing of up to 200 feet or more which is shirred and compacted to a much shorter length.
It is also common to use a casing sizing means in connection with the stuffing of relatively large casings which, for example, may range between 50 and 200 millimeters in diameter. These casings have a relatively thick wall, often reinforced with a fibrous web. The stuffing of these larger casings is often facilitated by diametrically stretching the casing just prior to stuffing.
Sizing means as may be used to diametrically stretch the casing perform several important functions. For example, stretching the casing to a correct diametrical size during the stuffing operation facilitates production of a stuffed casing product having a relatively uniform diameter throughout its length. This diametrical stretching can be accomplished by longitudinally passing the casing over the stationary sizing means and allowing the sizing means to stretch the casing to a predetermined diameter. This stretched casing diameter is related to the manufacturer's recommended stuffed diameter for a given unstretched casing size and is, or is near to, the final diameter of the stuffed product.
The friction between the longitudinally moving casing and stationary sizing means also creates an amount of drag or hold-back force on the casing. While this drag or hold-back, in part, contributes to the final diameter of the stuffed casing product, hold-back also determines the extent to which the casing is filled. In general, the greater the drag or holdback on the casing, the more fully stuffed and tightly packed the casing with the food product.
While diametrical sizing and holdback is desired to provide a uniform, fully stuffed encased product, there are times during the stuffing operation when the casing should be relatively free of the drag or hold-back force created by the sizing means. For example, during automatic stuffing operations using the larger sizes of casing, it may be periodically necessary to provide an amount of casing slack, as when the stuffing apparatus is operated to gather and close the casing around the ends of the stuffed product. Reducing the drag or hold-back force on the casing in order to slack the casing facilitates the gathering and closing operation.
Sizing means as used in stuffing the larger sizes of casing can have either a fixed diameter as shown for example in U.S. Pat. Nos. 4,007,761 and 4,335,488 or an adjustable diameter as shown in U.S. Pat. Nos. 3,457,588 and 4,202,075. The latter type, in turn, can comprise elements which are integral components of the stuffing apparatus (U.S. Pat. No. 3,457,588) or they can be attachable to the stuffing apparatus (U.S. Pat. No. 4,202,075).
In the present invention, the sizing means has the capability of expanding diametrically in order to provide the desired stretch and hold-back to the casing. Reversing this adjustment, that is, collapsing the sizing means reduces the hold-back force and provides slack casing as may be required for gathering and closing the casing over the ends of the encased food product.
In addition to these features, the sizing means of the present invention is readily adaptable to existing stuffing apparatus. When incorporated into a stuffing apparatus, the sizing means in its collapsed condition takes up little space around the stuffing horn so that even a shirred casing can be slipped over the stuffing horn. Thus the sizing means presents no problems with respect to the effort involved in locating a casing over the collapsed sizing means and onto the stuffing horn of such apparatus.
A still further feature of the present invention is that it is adaptable for implanting within a casing so that it can be sold together with the casing as a casing article. In this instance, the sizing means, together with the casing, is mounted to the stuffing apparatus and the sizing means operably connected to the apparatus so as to permit the sizing means to perform its sizing function during the stuffing of the casing.